Compression locks for x-ray spot film devices



' June 23, 1959 s. YERKOVICH COMPRESSION LOCKS FOR X-RAY SPOT FILM DEVICES 2 Sheets-Sheet 1 Filed July 7, 1958 INVENTOR. SMAON YERKOW H n 23,1959 SQYE'RKOWH 2,892,088

- COMPRESSION LOCKSFOR X-RAY SPOT FILM DEVICES Filed July '7, 1958 2 Sheets-Sheet'Z INVENTOR. SWON YERKQVKIH ASS\GNEE United States Patent Simon Yerkovich, Los Angeles, Calif., nssignor to Le Roy J. 'Leishman, Los Angeles, Calif.

Application July 7, 1958, Serial No. 746,869

3 Claims. (Cl. 250-58) The invention herein disclosed pertains to braking mechanisms for longitudinally movable devices, and more particularly to what is known as compression locks in X- ray spot film devices.

X-ray spot film devices embody a fluoroscopic screen and a means for moving an encased film into and out of the X-ray beam for making instantaneous radiographs of what the doctor sees on the fluoroscopic screen. These devices are attached to an elevator or carriage that is mounted for translational movement upon what is known as a fluoroscopic tower that extends from the bottom of the table past the side of the table and then upward in a direction at right angles to the table top. This carriage arrangement makes it possible to move the spot film device toward or from the table top in order to bring it into close proximity to bodysections of different thicknesses It is then necessary in a large amount of fluoroscopic and radiographic work to lock the spot film device or tunnel in its adjusted position in order to keep it against the patient. This is done by immobilizing the carriage with respect to the tower. The locking mechanisms used for this purpose are customarily called compression locks.

Various types of compression locks have heretofore been used. One type utilizes a rack extending longitudinally of the tower, and the carriage that transverses the tower and carries the spot film device is equipped with a toothed member that is usually spring loaded toward the rack for engagement therewith so that the toothed member may be held out of engagement with the rack while moving the tunnel and carriage along the tower. Some of these racks are sawtoothed and cooperate with a mating sawtoothed member on the carriage. This arrangement permits the carriage to be pushed down the tower with the toothed braking member slipping over the sloping surfaces of the teeth' on the rack. When movement in the opposite direction is attempted, the teeth of the braking member and rack interlock.

Other braking devices utilizes a manually operable gripping member on the carriage that engages one surface of a longitudinally extending member on the tower. Still'other locks utilize a ferrous strip on the tower that is engaged by an electro-magnet on the tower carriage when it is desired to immobilize the spot film device with respect to the patient. Brakes of this type have the disadvantage of requiring the current to remain on in order to maintain the braking effect.

The instant invention is a considerable improvement over past compression locks because, among other things, it utilizes self-equalizing brake shoes that engage opposite surfaces of a portion of the tower.

The structure of the incident mechanism is such that it may be made a part of the counterbalancing assembly inside of the tower, it being customary in the art to counterbalancethe spot film device and carriage by means of an oppositely moving counterweight insid'eof the tower that isconnected to the carriage by appropriate cables running on pulleys. By thus making the braking mechr 2,892,088 Patented June 23,. 1959 r? I we anism a part of the counterbalancing weight assembly, no extra weight is added to the total weight of the equipment by the inclusion of such a compression lock in the spot film device and tower combination.

Accordingly, one of the objects of the incident invention is to provide a brake that will frictionally engage opposite surfaces inside the fluoroscopic tower.

Another object is to make the pressure applied by the braking shoes self-equalizing.

Another object is the provision of a simple actuating means for moving the brake shoes into engagement with the surfaces against which they grip.

Another object is the provision of a simple detent for holding the braking shoes in engagement with the surfaces which they grip.

Another object is the provision of a simple unlocking means whereby a spring releases the brake shoes from their braking positions.

A further object is to supply a detent arrangement for holding the locking mechanism in an unlocked position.

An additional object is to make it possible to apply or release the brake by electrically operable means.

Still another object is to provide an electrically operable brake of the type described that will not require the current to remain on in order to hold the brake either on or 01f.

In the drawings:

Fig. 1 is a plan view of my braking mechanism looking down into the tower.

Fig. 2 is a section taken substantially on line 2-2 of Fig. 1.

Fig. 3 is an elevation view of my one side of the tower removed.

In one embodiment of my invention, I employ channel shaped lever members 1 and 2 pivoted respectively on bolts 3 and -4 that are mounted on a platform 5 supported on one end of a plate 6 which normally carries the counterbalancing weights on the inside of the tower.

Other channel-shaped members 7 and 8 are rigidly mounted substantially as shown onthe first mentioned channel-shaped members 1 and 2 respectively. 7

Blocks of rubber or other appropriate braking,material 9 and 10 are cemented or otherwise appropriately attached to the inside of the channel members 7 and 8, the whole assembly being so disposed that in certain angular positions of the lever channels 1 and 2, the braking shoes 9 and 10 will engage the opposite inner walls 11 and 12 of the channel-shaped member 13 forming one side of the fluoroscopic tower indicated generally.

mechanism,

.by the numeral 14. v v The plate 6 is movably mounted by means that are immaterial to the present invention to permit the plate and the various components mounted thereon to move transversely inside the tower.

noids 18 and 19 respectively.

and 26 are urged into'engagement with the leaf springs 21 and 22 respectively by the action of expansion spring 22. collapse slightly so that the ball bearings will glide;

over the peaks 23 and 24 and come together on the 27 appropriately attached either to members 1 and 2' or members 7 and 8.

When the cores 1-6 and 17 of the solenoids 18 and 19;,

move to the left, the beryllium copper springs 21 and The attached cores or plungers 16 and 17 move longitudinally inside the mic.

parallel portions 28 and 29 or the adjacent sloping portions of springs 21 and 22 under action of spring 27.

When the cores 16 and 17 move to the right, the peaks 23 and 24 of the springs ride between the ball bearings, thus pushing the channel members outwardly so that the braking elements 9 and 10 engage the surfaces 11 and 12 under the action of springs 21 and 22. Any tendency of the armatures 16 and 17 tomove to the left is resisted by the sloping sides of the springs 23 and 24 against the ball bearings.

If solenoid 19 is used for locking, the energizing of the coil will cause the armatures or cores to be drawn toward the right. The energizing of solenoid 18 will move the cores and the attached leaf springs to the left, thus releasing the brake. a

The tension of the brake may be controlled during manufacture by changing the angles of the sloping sides of the springs or by controlling the separation of their outer ends which may be appropriately spaced by washers placed between the springs and around the bolt which extends through both of the springs and serves to clamp the ends of the springs and such spacers as may be between them. The pressure for this clamping arrangement is provided by nut 31. Inasmuch as springs 28 and 29 are of course resilient, they are free to move slightly as a unit from one side to the other in accordance with the pressure exerted upon them by the ball bearings 25 and 26 as the brake shoes 9 and 10 engage the surfaces 11 and 12. It will be seen that this floating action of the springs 21 and 22 makes the pressure on the two brake shoes self-equalizing.

The solenoids 18 and 19 may be operated by individual switches 32 and 33 in a circuit such as that shown in Fig. 4. There is a disadvantage to this circuit, however, in that the inadvertent operation of both switches at the same time would energize both solenoids simultaneously. I therefore prefer the circuits shown in Figs. 5, 6 and 7.

In Fig. 5, the arm 34 of switch 32a is held against contact 35 by means of the spring 36, and the armature 37 and switch 33a is held against contact 38 by means of spring 39. If solenoid 18 is to be energized, the pole 35 of switch 32a is pressed against contact 40. The current then flows from source 41 through conductors 42 and 43 to contact 38 and then through pole 37 and conductor 44 to pole 34 and contact and then through conductor 45 to solenoid 18. Ifsolenoid 19 is to be energized, the pole 37 of switch 33a is held against contact 46. In this case, the current to pole 37 is received from conductors 42 and 47 through contacts 35, armature 34 and conductor 44. The engagement of arm 37 with contact 46 thus energizes solenoid 19 through conductor 48. If both switches 32a and 33a should be operated together, it will be clear from a glance at the circuit that no current whatever can flow. This circuit is thus electrically interlocked against the energizing of both solenoids simultaneously.

Another alternate circuit is that shown in Fig. 6 in which the switch 49 is spring loaded to center. Either of the solenoids may be energized by this single-pole double-throw arrangement.

It is of course inadvisable for the current to remain on in these solenoids. This is true not only from a current consumption viewpoint but also, especially in the case of alternating current solenoids, because the current might cause vibration or chattering. The operator accordingly merely presses the button, which causes the solenoid to operate the brake so rapidly that the brake is applied before the operator has time to remove his finger, which he normally would do at once.

The switches in Figs. 4, 5 and 6 are thus momentarily operated.

Fig. 7 shows my preferred arrangement. This operates in connection with a single-pole double-throw toggle switch I 4 50 shown physically in Figs. 1, 2 and' 3 and diagrammatically in Fig. 7.

In this arrangement, the movement of the plungers 16 and 17 actuates the single-pole double-throw toggle switch 50 and reverses the circuit to the solenoids. This is accomplished by means of a U-shaped member 51 attached by any appropriate means to the cores 16 and 17 of the solenoids. In the positions shown in Figs. 1, 3 and 7, solenoid 19 has just been energized, and the aim 52 of the U-shaped member 51 has engaged the arm or bat-handle 53 of the toggle switch, causing its pole 54 to break engagement with contact 64 and to make engagement with contact 55. If pole 56 of single-pole double-throw switch 60 is moved into engagement with contact 57, current will flow from source 58 through conductor 59 to armature 56 and thence through contact 57 and conductor 62 to solenoid 18. The movement of the plungers or cores 16 and 17 to the left will then cause arm 61 of the U-shaped bracket 51 attached to these cores to strike handle 53, thus breaking the engagement of pole 54 with contact 55 and de-energizing solenoid 18. Arm 54 will then be in engagement with contact 64 so that the subsequent action of switch 60 will energize solenoid 19. With this arrangement, the solenoids are only momentarily energized even though the pole 56 of switch 60 remains in engagement with contact 63 or 57. Switch 60 may thus, if desired, be a toggle switch, two separate switches, or a single-pole doublethrow switch of a common type now on the market that moves from one alternate contact to the other on successive presses of a push button.

It is possible, of course, to use a rack or racks in place of the surfaces 11 and 12 of Fig. 1 and to replace the braking shoes with appropriate toothed members. Various other modifications and substitutes may also be made in the structure shown and described, and the elements may be rearranged and transposed without departing from the broad spirit of the invention as succinctly set forth in the appended claims.

My claims are:

1. A look for a carriage that traverses the fluoroscopic tower of an X-ray machine including: A counterbalancing member transversely movable with respect to the tower; two opposite internal surfaces extending longitudinally of the tower; a pair of pivoted elements supported by said member; each of said elements carrying a brake shoe for engaging a difierent one of said surfaces; two rollers each mounted on one of said elements; two solenoids having aligned and connected plungers, each of said solenoids acting when energized to move the connected plungers in a direction which is opposite for each solenoid; a pair of leaf springs attached to the outer end of said plungers and extending between said rollers, inntermediate portions of said leaf springs bowed away from each other to form opposite peaks with sloping approaching surfaces, the portions of said springs near said peaks acting to urge said rollers outwardly to press said brakes against said surfaces, and said peaks acting as detents to prevent said plungers from moving away from said rollers when the peaks are on the sides of said rollers opposite from the solenoids.

2. The device of claim 1 plus resilient means attached to said elements for withdrawing said shoes from said surfaces when said plungers move said peaks to a position between the plungers and the rollers.

3. The device of claim 1 plus means for holding together the outer ends of said leaf springs and such spacers as may be disposed between them for increasing the outward pressure of the bowed-out portions of the leaf springs against the rollers.

References Cited in the file of this patent UNITED STATES PATENTS 2,823,315 Stava et a1. Feb. 11, 1958 

